CN2475013Y

CN2475013Y - Steady state large viewing field polarizing interference image formation spectrograph

Info

Publication number: CN2475013Y
Application number: CN 01213108
Authority: CN
Inventors: 张淳民
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-03-15
Filing date: 2001-03-15
Publication date: 2002-01-30
Anticipated expiration: 2011-03-15

Abstract

The utility model relates to a steady state large viewing field polarizing interference image formation spectrograph for simultaneously obtaining target images and interference spectrum. The utility model is composed of a pre-optical lens assembly, a view field compensation type polarizing interferometer, a collecting optical lens and an area array detector, wherein the components are arranged coaxially; the polarizing interferometer comprises a polarizer, a view field compensation type Savart deflecting roundel and an analyzer. The Savart deflecting roundel is composed of two negative crystal or positive crystal Savart plates which are arranged side by side, and a half-wave compensating plate which is clamped between the two Savart plates, wherein the model number of the material of the half-wave compensating plate is different from the model number of the material of the Savart plates. The light axles of the two Savart plates respectively form an angle of 45 DEG and an angle of 135 DEG with the system light axle. The product has the advantages of stable state, large view field and high flux.

Description

The big visual field of stable state polarization interference imaging spectrometer

The utility model content belongs to the optical instrument technical field, relates to a kind of imaging spectrometer that can be used for obtaining simultaneously target shape image and interference spectrum.

Imager in the general concept belongs to the different optical instrument of two classes with spectrometer, the shape image that utilizes Image-forming instrument can obtain target is the two-dimensional space information of target, thereby the spectrum that utilizes spectral instrument can obtain target draws the structure and the chemical composition of material.In history, the also mutual independent development of this two quasi-instrument gets up.The eighties in 20th century, imaging spectrometer has appearred in the world, it is the combination of current imager and spectrometer, because it can obtain the two-dimensional space information and the one dimension spectral information of target simultaneously, dual-use function with imager and spectrometer, thereby obtain in space remote sensing, information, all many-sides such as scientific research, the national economic development and national security have extremely important using value, have demonstrated more and more wide application prospect.As at military aspect; it can be used for spaceborne (or airborne) the earth observation face of land and hidden military target, then can be used for astronomy and geophysical research, resource investigation, environmental monitoring, disease and pest forecast aspect civilian, take precautions against natural calamities relieve the people in stricken areas, soil alkalization and desertify control, forest cover protection, crops the yield by estimation, aerosol and wind field detection, instruments used for education etc.

Up to now, important stages such as optical filter type, color dispersion-type and interfere type have been experienced in the development of imaging spectrometer, and wherein the interference type imaging spectrometer is divided into time modulation type and spatial modulation type two big classes again.Because the spatially modulated interference imaging spectrometer has overcome time interferometric modulator imaging spectrometer and has needed high precision index glass drive system and real-time bad two big shortcomings, thereby it uses wave band wideer, stability is better, has potential high-throughout advantage, but the major defect that this imaging spectrometer exists is to contain slit in the device, cause the energy of the system of entering to be greatly limited, owing to the bending of far field interference fringe, its field angle is also done not quite (generally only being 1～2 °) simultaneously.During the nineties in 20th century, the report about polarization interference imaging spectrometer has appearred in this area, but before the utility model scheme proposes, has only the digital array scanning interferometer spectrometer (DASI) of U.S.'s development in 1996 in the world.DASI is a kind of polarization interference imaging spectrometer that belongs to the spatial modulation type, adopts Wollaston prism, angle to shear beam splitter and close-in target, and the shortcoming of existence is to contain slit in the instrument, and capacity usage ratio is too low, and field angle is also still less.

The purpose of this utility model is to provide a kind of big visual field of stable state polarization interference imaging spectrometer with advantages such as stable state, big visual field and high fluxs for the defective that overcomes prior art.

Be used to realize that the technical solution of foregoing invention purpose is such: the stable state polarization interference imaging spectrometer that is provided by along incident light to the coaxial preposition optical lens group that sets gradually, field-compensation type polarized interferometer, collecting optical lens and planar array detector (CCD) forms, polarized interferometer wherein partly comprises along the coaxial polarizer that sets gradually of systematic optical axis, savart polariscope and analyzer three part optical components, the half-wave retardation film compensated plate that said savart polariscope is folded between two blocks of savart plates by two negative crystal placed side by side or positive brilliant savart (Savart) plate and one and manufacturing materials model and savart sheet material material model are different constitutes, and the optical axis of two savart plates is at 45 and 135 ° of angles with systematic optical axis in same plane and respectively; The signal output part of planar array detector obtains input end by tie with the signal of Computer signal disposal system and connects.

Polarization interference imaging spectrometer described in the utility model belongs to the polarization interference imaging spectrometer of space-time mixed mode, it is lateral shearing beam-splitter that the difference of it and spatial modulation type polarization interference imaging spectrometer and great innovation are in having adopted the savart polariscope with field-compensation function, both there be not slit in the device, can accomplish big visual field (± 10 °) again, its flux is than high 2 orders of magnitude of color dispersion-type inteference imaging spectrometer, than the high N/2 of DASI doubly (N is the ratio of field stop width and DASI slit width in the device described in the utility model, and the N value is generally at 1～2 order of magnitude); This device is for the infinity target, but has advantages such as multispectral passage, high s/n ratio, high stability, linear light path, simple in structure and subminiaturization.

Below with reference to accompanying drawing behind the literary composition the utility model content is described further, this accompanying drawing is the structural representation of a kind of specific embodiment of the utility model.

As shown in the figure, this stable state polarization interference imaging spectrometer structure comprises preposition optical lens group 1, field-compensation type polarized interferometer 2, collects parts such as optical lens 3 and planar array detector 4, and the signal output part of planar array detector 4 connects by the signal input part of tie with Computer signal disposal system 5.

The main effect of preposition optical lens group 1 is the radiation that target light source is sent is collected, collimated and to reduce parasitic light.When target is far, think when the light beam that arrives instrument is parallel beam, preposition optical lens group can be removed, allow light directly enter polarized interferometer 2.

The core of field-compensation type polarized interferometer 2 is field-compensation type savart polariscopes, it is made by two blocks of identical negative crystal (as kalzit) plate or positive brilliant (as quartz)

plates

22,24 of thickness, the optical axis of two blocks of savart plates all in paper plane (XZ plane among the figure) and with systematic optical axis (Z axle) angle at 45, wherein the direction of optic axis of header board 22 respectively with X, Z axle forward angle at 45, the direction of optic axis of back plate 24 respectively with X-axis forward, Z axle negative sense angle at 45, two optical axises are vertical mutually.Between two blocks of

savart plates

22,24, accompany a half-wave retardation film compensated plate 23, the manufacturing materials model and the savart plate of this compensating plate is different, and (as the savart plate is negative crystal, then the half-wave retardation film compensated plate is positive brilliant, and vice versa), its optical axis and two savart board planes (paper plane) they are X, Y-axis forward angle at 45.The effect that the utility model is provided with half-wave retardation film compensated plate 23 mainly contains 2 points: first bit phase delay, to centre wavelength be into light, behind half-wave retardation film compensated plate 23, bit phase delay π, after can making the ordinary light process half-wave plate 23 in savart polariscope header board 22 like this, become extraordinary ray in the plate 24 of back, vice versa; It two is the compensating actions that play big visual field, material and thickness by suitably choosing half-wave plate 23 in the enforcement, the light path that two linearly polarized light eo and oe produce in the savart polariscope is compensated, that is to say that half-wave retardation film compensated plate 23 can produce a negative optical path difference to above-mentioned two linearly polarized light eo and oe, make and close optical path difference and obtain corresponding minimizing, so that to complete compensation---zero optical path difference is approaching.The half-wave retardation film compensated plate also can be made by identical with the savart polariscope fully special-shaped crystal slab of two block structures, and its thickness is decided according to field-compensation, is positioned between the two savart plates.During design, can determine the maximum optical path difference of polariscope according to the requirement of spectral resolution, after adopting said method to carry out " field-compensation ", make it to meet the requirements of maximum optical path difference and the resolution that needs, so just bigger field angle can be arranged, also promptly reach the purpose of the big visual field of wide-angle than no field-compensation situation.The polarizer 21 and analyzer 25 are divided into savart polariscope two ends, their polarization direction all with X, Y-axis forward angle at 45, can make the shearing displacement maximum like this.The effect of savart polariscope is that a branch of polarized light lateral shear that will be penetrated by the polarizer 21 is that two beam-emergence directions are parallel to incident beam and direction of vibration is vertical mutually and two linearly polarized lights at regular intervals, and two linearly polarized lights become behind analyzer 25 along the linearly polarized light of analyzer 25 polarization directions vibration.

The effect of collecting light lens 3 is that target emanation light is collected on the detector that is positioned at its focal plane, and two light interfere and form interferogram (striped) herein.Interference fringe is vertical with shear direction, and optical path difference is directly proportional with shearing displacement and detector size, is inversely proportional to imaging mirror focal length, and optical path difference is big more, and spectral resolution is high more.

Planar array detector 4 is the interference signal receiver, pushes away when sweeping with respect to target at instrument, can obtain the two-dimensional space information and the one dimension spectral information of target.

After Computer signal disposal system 5 is handled the interferogram signal of obtaining from detector 4, finally draw the spectral information and the image information of target.

The practical work process of the big visual field of this stable state polarization interference imaging spectrometer is such: preposition optical lens group 1 is collected radiation of light source, inject field-compensation type polarized interferometer 2 behind the collimation, be that collimated ray becomes behind the polarizer 21 along a branch of linearly polarized light of the polarizer 21 polarization directions vibration, behind field-compensation type savart polariscope, be two bundle vibration planes orthogonal linearly polarized lights by lateral shear, by becoming the on all four two bunch polarized lights of direction of vibration after analyzer 25 analyzings, meet on detector 4 through collecting optical lens 3 again, form interference fringe, rely on instrument to push away to sweep along the light beam shear direction and obtain complete interferogram, interferogram can obtain the spectral information and the multispectral image of target as calculated after the machine information disposal system.

Claims

1, the big visual field of a kind of stable state polarization interference imaging spectrometer, it is characterized in that it by along incident light to the coaxial preposition optical lens group (1) that sets gradually, field-compensation type polarized interferometer (2), collecting optical lens (3) and planar array detector (4) forms, wherein: polarized interferometer (2) comprises along the coaxial polarizer that sets gradually of systematic optical axis (21), field-compensation type savart polariscope and analyzer (25), said savart polariscope is by two blocks of negative crystal savart plates (22 placed side by side, 24) and one be folded in two negative crystal savart plates (22,24) the positive brilliant half-wave retardation film compensated plate (23) between constitutes, two savart plates (22,24) optical axis is at 45 and 135 ° of angles with systematic optical axis in same plane and respectively; The signal output part of planar array detector (4) obtains input end by tie with the signal of Computer signal disposal system (5) and connects.

2, the big visual field of stable state as claimed in claim 1 polarization interference imaging spectrometer, it is characterized in that said savart polariscope is made of the negative crystal half-wave retardation film compensated plate (23) that two blocks of positive brilliant savart plates (22,24) placed side by side and are folded between the two positive brilliant savart plates (22,24), the optical axis of two savart plates (22,24) is at 45 and 135 ° of angles with systematic optical axis in same plane and respectively.